In general, one end of a tube coupler is inserted into a body of an apparatus, and a tube such as a hose is inserted into the other end of the tube coupler to form a channel.
In the conventional tube coupler, as shown in FIGS. 1 and 2, when a stud member 20 is inserted into a socket member 10, a locking ring 30 installed at the outer circumference of the stud member 20 is shrunken along an inclined surface 12 formed at the end of the socket member 10. When the locking ring 30 of the stud member 20 is closely adhered to the inclined surface 12 of the socket member 10, the locking ring 30 is hooked by a right-angled hooking groove 14 formed at the inner circumference of the socket member 10, thereby connecting the stud member 20 to the socket member 10.
In addition, two seal rings 32 and 33 are positioned at the front and rear sides of the locking ring 30 in an axial direction. When the stud member 20 is inserted into the socket member 10, the seal ring 33 positioned at the front side passes the hooking groove 14 without any resistance, receives pressure in an orthogonal direction to the axis around a ring-shaped rib 16 formed at the inner circumference of the socket member 10, and maintains a pressured state between the stud member 20 and the socket member 10 in order to prevent leakage. The seal ring 32 positioned at the rear side is closely adhered to the inclined surface 12 of the socket member 10 before the locking ring 30 is hooked by the hooking groove 14. When the locking ring 30 is hooked by the hooking groove 14, the seal ring 32 receives virtual pressure in an inclined direction between the socket member 10 and the stud member 20 in order to prevent leakage.
A small-sized safety ring 35 installed at the end of the stud member 20 is hooked by a groove 17 formed at the inner circumference of the socket member 10 so that the stud member 20 can maintain an interim connection state not to be completely connected to the socket member 10. In the case that the stud member 20 is completely inserted into the socket member 10, the safety ring 35 is closely adhered to the inner circumference of the socket member 10 for performing a seal ring function for preventing a low pressure fluid from being externally leaked.
However, the conventional tube coupler has difficulty in a process because the seal rings 32 and 33, the locking ring 30 and the safety ring 35 are positioned in the socket member 10, and the inclined surface 12, the hooking groove 14, the groove 17 and the rib 16 have complicated shapes. Especially, when the socket member 10 is formed in an elbow type, if the tube coupler is fixed and processed to a chuck of a lathe by using an exclusive use jig, the center of gravity is moved to one side. It is thus difficult to perform a precision process due to serious vibration. In order to solve the foregoing problems, a balance weight is mounted on the jig, which complicates fabrication of the jig.
Moreover, the conventional tube coupler uses at least two seal rings 32 and 33. So as to install the seal rings 32 and 33, a plurality of hooking grooves 14, grooves 17 and ribs 16 must be formed in the socket member 10, and a large number of grooves and ribs must be formed in the stud member 20, which complicates a manufacturing process.